The answer to that question depends on whom you ask.
The sign in the pharmacy window might suggest flu season is already here, and the Centers for Disease Control and Prevention is urging everyone at least 6 months old to get a dose of prevention "as soon as possible."
But according to some infectious disease experts, the beneficial effects of a flu shot received in August or September could start to fade just as the virus kicks into high gear.
While doctors can never predict exactly when it will strike, the official start of flu season has long been October, with the number of cases typically peaking in February or even later.
